Track the recent changes in atcoder/ac-library

[qryxip]

• math, internal_math
  • #33: relax the constraints of floor_sum atcoder/ac-library#92
• math
  • Improve floor_sum atcoder/ac-library#88
  • Fix comment in math atcoder/ac-library#97
• maxflow
  • nit picking optimization for maxflow atcoder/ac-library#63
• mincostflow (I'm not sure)
  • optimize mcf atcoder/ac-library#82
• lazysegtree
  • Unify how to write the same operation atcoder/ac-library#105

[TonalidadeHidrica]

It is ideal that it is done before the language update, but we have only two weeks, so it may be too late.
Adding to the milestone, but the priority is low.